Question: how do you retrieve redundant satellites and debris originating from satellites in space?

We don’t retrieve them. So there are two things that can happen, Once the satellites life is over, if there is some fuel left, the Satellite will be slowed down where eventually it will fall out of orbit, and burn up in the atmosphere. The other option is to push it back further into space, which is what is known as a graveyard orbit and it will stay there until we run out of space – which won’t happen in our lifetime.